How are individual peripheral visceral organs controlled by the brain? Katz and Karten [49-56] have demonstrated the existence of a precise organotopic representation of the peripheral visceral organs in subnuclei of the nuc. tractus solitarius and the motor nucleus of the vagus (nTs-DMX). What are the central afferent and efferent connections of each organ specific subnucleus of nTs and DMX? Are there separate anatomical lemnisci for regulation of pulmonary, GI, pancreatic and cardoivascular systems between nTs-DMX and other regions of the brain, such as the hypothalamus? The differential afferent and efferent central connections of organ specific subnuclei of the nTs-DMX will be studied using histological methods, including ARG nTs-DMX is veritable storehouse of various peptides/transmitters of both extrinsic and intrinsic origin. Including SP, CCK, ENK, VIP, NT, DA, NE, 5-HT, GAD/Gaba and subsets CAT. Pilot studies have revealed their differential distribution in organ specific of the nTs-DMX. The origin, localization and ontogeny of these immunohistochemically distinct inputs will be investigated. These experiments will help clarify the potential mechanisms of neuronal regulation of individual viscera by the hypothalamus and the boichemical and pharmacological organization of nTs-DMX.